Control apparatus for balancing hoists



Feb. i3, 1968 o. M. ULBING 3,368,796

CONTROL AYPARATUS FOR BALANCING HOISTS Filed March 9, 1967 @2 26 i f I/ yHill l'niif..

INVENTOR A @TM-AR M. ULB/N6 l ATTORNEY United States Patent O 3 368 796 CONTROL APPARATUS FOR BALANCING HOISTS Otmar M. Ulbing, Berkshire, N.Y., assignor to Ingersoll- Rand Company, New York, N.Y., a corporation of New Jersey Filed Mar. 9, 1967, Ser. No. 621,857 11 Claims. (Cl. 254-168) ABSTRACT F THE DISCLOSURE A balancing hoist having an internal cylinder and pist0n arrangement which is provided with valves for controlling ythe ow of iluid from the cylinder, and which is connected to control the speed of the movement of the hoist drum.

Background of the invention The present invention relates to hoist apparatus and has more particular reference to balancing hoists of the type capable of providing a lifting force substantially balancing a load such that the latter may be vertically moved by the application of a relatively small force to the load.

An object of the present invention is to provide a balancing hoist which includes a new and improved means for controlling the speed at which the eifectlve length of the hoisting cable is Iadjusted during the operation of the balancing hoist.

Another object of the invention is to provide a balancing hoist including a new and improved means of the type set forth which is particularly constructed and arranged to control the speed at which the effective length of the hoisting cable is adjusted in both directions of the movement ofthe hoist drum.

Another 4object is to provide a balancing hoist including a new and improved means of the type set forth which is relatively simple and economical in construction and highly dependable and eflicient in operation.

Summary of the invention The aforegoing objects, and those other objects and advantages of the invention which will be apparent from the following description .taken in connection with the accompanying drawings, are attained by the provision of a balancing hoist comprising a casing containing a cavity, and a hollow hoist drum disposed in the cavity for rotation and axial movement therein. A cable is wound on the hoist drum such that it is adjusted in effective length during movement of the hoist drum, the cable projecting from the cavity and externally of the casing. A means is provided for causing pressurized fluid to effect movement of the hoist drum in the cavity. A cylinder and piston means is connected for relative movement, during movement of the hoist drum, at a speed variable with the speed of movement of the hoist drum; and a means, responsive to the relative movement of the cylinder and piston means, is provided for causing the cylinder and piston means to resist movement of the drum when the speed of the relative movement of the cylinder and piston means exceeds a predetermined speed.

Brief description of the drawings `Referring to the drawings:

FIG. l illustrates an elevational view, partially broken away and in section, of a balancing hoist including an embodiment of the present invention; and

FIG. 2 is an enlarged, elevational sectional view taken on line 2 2 of FIG. 1, looking in the direction of the arrows.

Description of the preferred embodiment Referring more particularly to the drawings wherein similar reference characters designate corresponding parts throughout the several views, FIG. 1 illustrates a balancing hoist designated generally as 10= which includes an outer casing 12 adapted to be mounted on an overhead support by a mounting hook 14. The casing 12 contains a cylindrical cavity 16, the opposing ends of which are closed by the right 4and left end walls 18' and 20, respectively, of the casing 12. A hoist drum 22 is disposed- Within the cavity 16 for rotation and axial movement in the latter and carries a hoisting cable 24 which projects from the cavity 16 externally of the casing 12. The end of the cable 24 external to the casing 12, as will be understood, carries a conventional, relatively heavy lift hook (not shown). i

The hoist drum 22, more specifically, comprises a circumferentially grooved, cylindrical outer wall or shell 26 which, as viewed in FIG. 1, is closed at its right end by an end wall 28. The shell 26 and the end wall 28 thus cooperate to define an internal cavity 30 which, as illustrated in FIG. 1, is open at the left end of the hoist drum 22. The cable 24 is wound around the external circumference of the shell 26 of the hoist drum 22 such that it is automatically adjusted in effective length during the aforedescribed rotation and axial movement of the hoist drum 22 in the cavity 16.

A pressure regulator 32 is mounted on the 4left end wall 29 of the casing 12 and, during the operation of the balancing hoist 10, connected through a conventional uid supply hose (not shown) to a source of pressurized air. The pressure regulator 32 is connected to an outlet pipe 34 which discharges into the cavity 30 of the hoist drum 22 such that pressurized air discharged by the pressure regulator 32 may be supplied to .the cavity 30. The pressure regulator 32, during the aforesaid operation of the balancing hoist 10, reduces the pressure of the pressurized air which it receives through the Huid supply hose and discharges such reduced pressure air through the output pipe 34 into the cavity 30. The pressure regulator 32 may be provided with an adjustment means for varying the pressure to which it reduces the pressurized air supplied by the fluid supply hose.

An exhaust hose 36 is connected at its upper end to the pressure regulator 32 and depends from the lett end wall 20 of the casing 12. The lower end of the exhaust hose 36 carries an operating lever designated generally as 38 which includes a manually operated valve. The operating lever 38 is adapted to be maintained at substantially head height such that it may be readily actuated by the operator of the balancing hoist 10 to selectively open, or close, the valve contained in the operating lever 38. When the operating lever 38 is actuated to open its contained valve, the exhaust hose 36 is exhausted to atmosphere such that, in tur-n, pressurized fluid .is exhausted from the pressure regulator 32 and the cavity 30. As long as the valve in the operating lever 38 is maintained in an open position, it prevents the accumulation of pressurized air in the cavity 30.

The internal circumference of the shell 26 is provided with a helical groove 40 which is engaged by a plurality of rollers, one of which is shown as 42 in FIG. l1. The rollers 42 aremaintained by individual supporting bolts 44 upon the inner end of a supporting bracket 46 which is rigidly connected to the left end wall 20 of the casing 12 and projects concentrically into the cavity 30 of the hoist drum 22. The rollers 42 include tapered and lconical peripheries 48 and are arranged about axes extending at acute angles to the longitudinal axis of the cavity 16 in the casing 12.

The helical groove 40 on the internal circumference of the shell 26 is constructed such that, when the hoist drum 22 rotates in a clockwise direction as viewed from the end wall 28, the hoist drum 22 is caused to move axially to the right, as viewed in FIG. 1. The outlet pipe 34 is arranged to discharge pressurized air into the chamber 50 formed `between the outer periphery of the supporting bracket 46 and the inner periphery of the hoist drum 22. Thus, as will be seen, pressurized air flow into the chamber 5t) from the outlet pipe 34 urges the hoist drum 22 axially towards the right, as viewed in FIG. 1, and in a clockwise direction, as viewed from the end wall 28.

The helical groove 52 formed in the external circumference of the shell 26 is constructed in the same direc tion of rotation as the helical groove 40 and, preferably, is formed with the same pitch as the helical groove 40. This construction, as will be understood, insures that the depending portion of the cable 24 is maintained in a stationary vertical plane during the movement of the hoist drum 22 in the casing 12.

The present invention comprises the provision of a new and improved apparatus for controlling the speed at which the cable 24 is adjusted in effective length during the movement of the hoist drum 22 by limiting the speed of the movement of the hoist drum 22. Generally considered, this new and improved apparatus comprises a cylinder and piston means which is disposed in the cavity 30 of the hoist drum 22 and connected to the hoist drum 22 t0 resist movement of the latter when its speed exceeds a predetermined speed. More specically, a hollow cylinder 54 is rigidly mounted on the left end wall 20 of the casing 12 by a mounting bolt 55 such that it extends axially towards the end wall 28 of the hoist drum 22. Apiston, adapted for movement relative to the cylinder 54, is connected to the end wall 28 for axial movement with the hoist drum 22.

The piston comprises a piston head S6, slidably disposed within the cylinder 54, which is rigidly mounted upon one end of a piston rod 58. The piston rod 58 extends through an opening 59 in the supporting bracket 46 and projects from the cavity 30 through an opening 60 formed in the end wall 28. The piston rod 58 rigidly carries a collar 64 which includes an annular, outwardly projecting ange portion 66, slightly spaced from the end wall 28 within the cavity 30, and an annular spacer portion 68 which projects through the opening 60 circumferentially around the piston rod 58. The free end of the piston rod 58 is circumferentially threaded and carries an internally threaded mounting nut 62 which is threaded into abutment with the spacer portion 68 of the collar 64. The opening 60 is constructed of suitable cross section to provide a clearance 61 between the spacer portion 68 of the collar 64 and the walls of the opening 60 to permit rotation of the hoist drum 22 independently of the piston rod 58. A packing means, designated generally as 70, is provided circumferentially around the spacer portion 68 to prevent fluid leakage through the clearance 61. This connection of the piston rod 58 to the end wall 28, thus, ensures that the piston is axially movable with the hoist drum 22, but permits rotation of the hoist drum 22 independently of the piston.

A uid passage or bore 72 is formed in each end cap of the cylinder 54 in communication with the cavity contained in the cylinder 54. The bores 72, as illustrated in FIG. 1, are connected by separate valve bores 73 to individual uid conveying hoses 74 which, in turn, are connected to a common uid conveying hose 76 by a connector 78. The uid conveying hose 76 is connected to a compensating reservoir 80, containing a supply of pressurized fluid, carried by the left end wall 20 of the easing 12. A valve 82 is disposed in each of the valve bores 73 for controlling the flow of pressurized uid through the latter. FIG. 2 illustrates the details of construction of one of the valves 82. It will be understood, however, that as the valves 82 are each formed of identical construction, the following description of FIG. 2 is equally applicable to both of the valves 82.

More specifically, the valve 82 which is illustrated in FIG. 2 comprises a piston 84 containing :l plurality of longitudinally extending, peripheral grooves 86. The peripheral grooves 86, as will be understood, comprise the sole path for fluid to flow by the piston 84. The piston 84 is slidable between an open position, illustrated in FIG. 2, wherein a limited quantity of fluid is permitted to flow through the peripheral grooves 86 and a closed position against the valve seat wherein uid ow through the valve bore 73 is prevented. The piston 84, moreover, is biased to its illustrated open position by a spring 88 such that it is normally in such open position.

During the operation of the aforedescribed balancing hoist 1t), the casing 12 is mounted on an overhead support by the mounting hook 14 such that the axial movement of the hoist drum 22 is in a generally horizontal direction. Thereafter, with the hoist drum 22 in the position illustrated in FIG. 1, the cable 24 may be varied in effective length by causing pressurized air to be supplied through the outlet pipe 34 to the chamber 50. The pressurized air which is thus supplied to the chamber 50, and the rollers 42, cause the hoist drum 22 to be moved axially to the right, as viewed in FIG. 1, and simultaneously rotated in a clockwise direction, as viewed from the end wall 28. This movement of the hoist drum 22, as will be understood, automatically varies the effective length of the cable 24.

During the aforedescribed movement 0f the hoist drum 22, fluid in the cylinder 54 intermediate the piston head 56 and the end cap of the cylinder 54 at the right end, as viewed in FIG. 1, exhausts through the valve 82 contained in the valve bore 73 which communicates with the bore 72 in said right end cap. When, however, the movement of the hoist drum 22 exceeds a predetermined speed, the fluid flowing to the aforedescribed valve 82 actuates the piston 84 to move the latter to its closed position against the valve seat 90. Thereafter, the cylinder and piston apparatus prevents further movement of the hoist drum 22.

Similarly, when the hoist drum 22 is traveling towards the left end wall 20 of the casing 12, the valve 82 positioned in the left end cap, as viewed in FIG. 1, controls the exhausting of uid from the cylinder 54 to cause the cylinder and piston apparatus to prevent further movement of the hoist drum 22 when the movement of the latter exceeds a predetermined speed.

From the aforegoing, it will `be seen that I have provided new and improved means for accomplishing all of the objects and advantages of my invention. It will be understood, however, that, although I have hereinbcfore illustrated and speeitically described only one embodiment of my invention, my invention is not limited merely to this specifically illustrated and described embodiment but also contemplates other embodiments and variations employing the concepts and teachings of this invention.

Having thus described my invention, I claim:

`1. A balancing hoist comprising:

a casing containing a cavity;

a hollow hoist drum disposed in said cavity for rotation and axial movement therein;

a cable wound on said hoist drum to be adjusted in eective length during movement of said hoist drum and projecting from said cavity externally of said casing;

means for causing pressurized iluid to effect movement of said hoist drum in said cavity;

cylinder and piston means connected for relative movement, during movement of said hoist drum, at a speed variable with the speed of movement of said hoist drum; and

means responsive to the relative movement of said cylinder and piston means for causing said cylinder and piston means to resist movement of said hoist drum when the speed of the relative movement of said cylinder and piston means exceeds a predetermined speed.

2. A balancing hoist according to claim 1, further comprising:

said cylinder and piston means including a cylinder,

and a piston disposed within said cylinder; and said resisting causing means comprising valve means for controlling the uid exhausted from said cylinder. 3. A balancing hoist according to claim 2, further comprising:

said cylinder and said piston being disposed within said hoist drum. 4. A balancing hoist according to claim 2, further comprising:

said cylinder being connected to one of said hoist drum and said casing; and said piston being connected to the other of said hoist drum and said casing. 5. A balancing hoist according to claim 4, further comprising:

said valve means comprising a valve for controlling the uid exhausted from each of the ends of said cylinder. 6. A balancing hoist according to claim 5, further comprising: said cylinder being connected to said casing; and said piston being connected to said hoist drum for axial movement with said hoist drum. 7. A balancing hoist according to claim 5, further comprising:

said hoist drum being formed to include a cylindrical shell having grooves which extend circumferentially around its outer circumference, and plate means closing one end of said cylindrical shell; and said one of said cylinder and said piston which is connected to said hoist drum being connected to said plate means. 8. A balancing hoist according to claim 5, further comprising:

each of said valves being normally in a position to allow lluid to escape from said Icylinder and being movable to a position to prevent uid from escaping from said cylinder.

9. A balancing hoist according to claim 5, further comprising:

means for biasing each of said valves to a position to allow uid to escape from said cylinder whereby said Valves are ea-ch responsive to a predetermined flow of iluid from said cylinder to move to a position preventing uid from escaping from said cylinder.

10. A balancing hoist according to claim 9, further comprising:

means for communicating fluid passing through said valves to a common reservoir.

11. A balancing hoist comprising:

a casing containing a cavity;

a hollow hoist drum disposed in said cavity for rotation and axial movement therein;

a cable wound on said hoist drum to be adjusted in effective length during movement of said hoist drum and projecting from said cavity externally of said casing;

means for causing pressurized uid to effect movement of said hoist drum in said cavity; and

means connected to said casing and said hoist drum relatively movable, during movement of said hoist drum, at a speed variable with the speed of movement of said hoist drum and operable, when the speed of movement of said hoist -drum exceeds a predetermined speed, to resist movement of said hoist drum.

References Cited UNITED STATES PATENTS 3,286,989 ll/l966 Bangerter 2511-168 3,314,657 4/1967 Prudhomme 254-189 3,325,148 6/1967 Powell 254-l68 EVON C. BLUNK, Primary Examiner.

H. C. HORNSBY, Assistant Examiner. 

